Nota:This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. Pérez-Montero, E., Hägele, G.F., Contini, T. and A.I. Díaz. Neon and argon optical emission lines in ionized gaseous nebulae: implications and applications. Monthly Notices of the Royal Astronomical Society 381 (2007): 125-135